Temperature-dependent absorption edge in AgGaS2 compound semiconductor
Temperature-dependent absorption edge in AgGaS2 compound semiconductor
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AgGaS2 化合物半导体中与温度相关的吸收边
DOI：
10.1016/j.jallcom.2004.07.031
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Y. Choi
中科院分区：
文献类型：
--
作者：
S. Eom;D. J. Kim;Y. Yu;Y. Choi
我们生长出了高质量的黄铜矿结构AgGaS 2单晶。使用光学吸收测量，通过Elliott-Toyozawa模型确定能带隙。结合AgGaSe_2化合物在T <100 K时的反常带隙变化进行了讨论。在100- 300 K温度范围内，用Urbach尾解释了指数增长的吸收尾。得到了该体系的特征Urbach参数，包括陡度参数和Urbach能随温度的变化关系，以及有效声子能量预测ω.吸收光谱的陡度主要是由热无序的影响，而不是结构无序和/或偏离化学计量。
We have grown high-quality AgGaS2single crystals with a chalcopyrite structure. Using an optical absorption measurement, the energy band gap was determined by means of the Elliott-Toyozawa model. The anomalous variation of energy band gap at T < 100K is discussed in conjunction with AgGaSe2compound displaying the same behavior. The exponentially increasing absorption tail was explained in terms of a Urbach tail in the temperature range of 100–300K. Characteristic Urbach parameters, including the steepness parameter and Urbach energy as a function of temperature, as well as effective phonon energy ħω, were obtained. The steepness of the absorption spectra is dominated by the effect of the thermal disorder rather than the structural disorder and/or the deviation from the stoichiometry.